JP2000119325A - Production of syndiotactic 1,2-polybutadiene and catalyst composition based ion iron used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a syndiotactic 1,2-polybutdiene and to produce a catalyst composition based on ion therefor. SOLUTION: This catalyst composition suitable for use when polymerizing 1,3-butadiene and producing a syndiotactic 1,2-polybutadiene comprises (a) an iron-containing compound, (b) a dihydrocarbyl hydrogenphosphite and (c) an organoaluminum compound. The use of an environmentally hazardous component, e.g. carbon disulfide and a halogen-substituted solvent is avoided by using the catalyst composition. The melting temperature of the syndiotactic 1,2- polybutadiene can be changed within the range from about 100 to about 200 deg.C by changing the catalyst components and the componental ratio. It is extremely favorable that the melting temperature can be changed within the wide range by using the simple catalyst composition. The syndiotactic 1,2-polybutadiene can be used as a plastic or as an additive for a rubber composition. In this case, syndiotactic 1,2-polybutadiene can be crosslinked together with a usual rubber using a usual crosslinking agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to (a) an iron-containing compound and (b)
The present invention relates to a catalyst composition comprising dihydrocarbyl hydrogen phosphite and (c) an organoaluminum compound, and to the polymerization of 1,3-butadiene to produce syndiotactic 1,2-polybutadiene.
Syndiotactic 1,2-polybutadiene is a thermoplastic resin, which can be cured with ordinary rubber due to the residual unsaturation.

[0002]

BACKGROUND OF THE INVENTION Syndiotactic 1,2-polybutadiene has a thermoregular structure in which vinyl groups present as side chains are alternately located on opposite sides of a polymer backbone composed of carbon-carbon bonds. It is a plastic resin. Syndiotactic 1,2-polybutadiene is
It is a unique material that has both the properties of plastic and the properties of rubber. Therefore, syndiotactic 1,
2-Polybutadiene has many uses. For example,
Films, fibers and molded articles can be produced using syndiotactic 1,2-polybutadiene.
It is also possible to blend it with rubber and cure it with it.

[0003] Syndiotactic 1,2-polybutadiene can be prepared by solution polymerization, emulsion polymerization or suspension polymerization. The syndiotactic 1,2-polybutadiene obtained from solution, emulsion or suspension polymerization typically has a melting temperature in the range of about 195 ° C to 215 ° C. However, for processability reasons, it is desirable for the syndiotactic 1,2-polybutadiene to have a melting temperature generally less than about 195 ° C so that it is suitable for practical use.

In the production of syndiotactic 1,2-polybutadiene, various transition metal catalyst systems based on cobalt, titanium, vanadium, chromium and molybdenum have been reported in the prior art (for example, by L. Porri and Giarrusso, Comprehensive
e Polymer Science, G .; C. Eas
tmond, A .; Ledwith, S.M. Russo and P.M. Edited by Sigwalt, Pergamon Pr
ess: Oxford, 1989, vol. 4, p. 53). However, such catalyst systems exhibit a low catalytic activity or poor stereoselectivity for the most part, and in some cases result in polymers with low molecular weight or crosslinked polymers that are not suitable for commercial use, so Is not actually used at all.

The following cobalt-based catalyst systems are well known for commercial scale production of syndiotactic 1,2-polybutadiene: (1) bis (acetylacetone) cobalt / triethylaluminum / water / triphenyl Phosphine (U.S. Pat. Nos. 3,498,963 and 4,182,813; Japanese Patent Publication No. 44-32626 (assigned to Nippon Synthetic Rubber Co., Ltd.); and (2) tris (acetylacetone) cobalt / triethylaluminum /
Carbon disulfide (U.S. Pat. No. 3,778,424;
2-19, 892, 81-18, 127, 74-17,
666 and 74-17,667 JP-A-81-88,40
8, 81-88, 409, 81-88, 410, 75-
59,480,75-121,380 and 75-12
1,379 (transferred to Ube Industries, Ltd.). The above two catalyst systems also have significant disadvantages.

The syndiotactic 1,2-polybutadiene obtained when using the bis (acetylacetone) cobalt / triethylaluminum / water / triphenylphosphine system has very low crystallinity. In addition, such catalyst systems exhibit sufficient catalytic activity only when halogenated hydrocarbon solvents are used as the polymerization medium, but halogenated solvents have toxicity problems.

In the case of the tris (acetylacetone) cobalt / triethylaluminum / carbon disulfide system, carbon disulfide is used as one of the catalyst components. Due to its high volatility, unpleasant odor and low flash point as well as toxicity, carbon disulfide is difficult and dangerous to use and is released to the atmosphere in small quantities Expensive security measures are required to prevent the Furthermore, the syndiotactic 1,2-polybutadiene obtained when using this catalyst system has a very high melting temperature (2.
(Within the range of 00 to 210 ° C.), it is difficult to process such a polymer. Catalyst modifier (mo
Although it is possible to lower the melting temperature of syndiotactic 1,2-polybutadiene by using a fourth catalyst component, the presence of such a catalyst modifier also results in catalyst activity and polymer yield. Adversely affect Accordingly, the industrial use of the two prior art cobalt-based catalyst systems described above requires a number of limitations.

Coordination catalyst systems based on iron-containing compounds, such as iron (III) acetylacetonate / triethylaluminum, have been known for many years in the prior art, but they have been shown in the polymerization of 1,3-butadiene. The activity is very low and the stereoselectivity is poor, and sometimes oligomers, liquid low molecular weight polymers or crosslinked polymers are obtained. Thus, such prior art iron-based catalyst systems have not been used industrially at all.

[0009]

SUMMARY OF THE INVENTION One object of the present invention is to provide syndiotactic 1, which has various melting temperatures and syndiotactic properties and does not have the above-mentioned disadvantages of the prior art.
2--butadiene.

Another object of the present invention is to provide a method for efficiently producing the above-mentioned syndiotactic 1,2-polybutadiene.

It is a further object of the present invention to provide a versatile and inexpensive catalyst composition exhibiting high catalytic activity and stereoselectivity suitable for the production of the above-mentioned syndiotactic 1,2-polybutadiene.

It has been found that the intended syndiotactic 1,2-polybutadiene can be efficiently produced by polymerizing 1,3-butadiene using a specific iron-based catalyst composition.

More specifically, the present invention relates to a catalyst composition which can be used when a 1,3-butadiene monomer is stereospecifically polymerized to produce a syndiotactic 1,2-polybutadiene. The catalyst composition comprises (a) an iron-containing compound, (b) dihydrocarbyl hydrogen phosphite, and (c) an organoaluminum compound.

[0014] The present invention further relates to a process for producing syndiotactic 1,2-polybutadiene, comprising the steps of:
It consists of polymerizing a butadiene monomer.

[0015] A number of highly beneficial and remarkable advantages are realized using the process and catalyst compositions of the present invention. For example, using the method and catalyst composition of the present invention, syndiotactic 1,2-polybutadiene can be obtained in a relatively short polymerization time and in high yield even with a small amount of catalyst. Additionally and more importantly, the catalyst compositions of the present invention include the highly volatile and toxic flammable carbon disulfide typically used in some prior art catalyst systems. The absence of carbon disulfide eliminates the toxicity, unpleasant odor, danger and costs associated with the use of carbon disulfide. In addition, the catalyst compositions of the present invention exhibit high catalytic activity in a wide range of solvents, including non-halogen substituted solvents such as environmentally preferred aliphatic and cycloaliphatic hydrocarbons. included. In addition, although the catalyst compositions of the present invention are iron-based, iron compounds are generally stable, non-toxic, inexpensive and readily available. Furthermore, the catalyst composition of the present invention is very versatile and can produce a wide range of melting temperatures of syndiotactic 1,2-polybutadiene without having to use a catalyst modifier as the fourth catalyst component.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The catalyst composition of the present invention comprises the following components: (a) an iron-containing compound, (b) dihydrocarbyl hydrogen phosphite, and (c) an organoaluminum compound.

As the component (a) contained in the catalyst composition of the present invention, various iron-containing compounds can be used.
In general, it is advantageous to use iron-containing compounds which are soluble in hydrocarbon solvents, such as, for example, aromatic, aliphatic or cycloaliphatic hydrocarbons. Nevertheless,
Catalytically active species can also be generated by simply suspending the insoluble iron-containing compound in the polymerization medium. Therefore, no limit should be placed on ensuring the solubility of the iron-containing compound.

The iron of the iron-containing compound used in the catalyst composition of the present invention can be in a variety of oxidation states, including, but not limited to, oxidation states of 0, +2, +3, and +4. Is included. The use of a divalent iron compound in which iron is in the +2 oxidation state (also called ferrous compound) and a trivalent iron compound in which iron is in the +3 oxidation state (also called ferric compound) It is suitable. Suitable types of iron-containing compounds that can be used in the catalyst compositions of the present invention include, but are not limited to, iron carboxylate, β-diketone iron, iron alkoxide or aryl oxides, iron halides, pseudo Includes iron halides and organic iron compounds.

Some specific examples of suitable iron carboxylate include iron (II) formate, iron (III) formate, iron acetate (I)
I), iron (III) acetate, iron (II) acrylate, iron (III) acrylate, iron (II) methacrylate, iron (III) methacrylate, iron (II) valerate, iron (II) valerate ( III), iron gluconate (II), iron gluconate (I
II), iron (II) citrate, iron (III) citrate,
Iron (II) fumarate, iron (III) fumarate, iron (II) lactate, iron (III) lactate, iron (II) maleate,
Iron (III) maleate, iron (II) oxalate, iron (III) oxalate, 2-ethylhexanoic acid (2-ethyl
lhexanoate iron (II), iron (III) 2-ethylhexanoate, iron (II) neodecanoate, iron (III) neodecanoate, iron (II) naphthenate, iron (III) naphthenate, iron (II) stearate ), Iron (III) stearate, iron (II) oleate, iron (III) oleate, iron (II) benzoate, iron (II) benzoate
I), iron (II) picolinate and iron (II) picolinate
I).

Some examples of suitable iron β-diketones include iron (II) acetylacetone, iron (III) acetylacetone, iron trifluoroacetylacetone (I
I), iron (III) trifluoroacetylacetone, iron (II) hexafluoroacetylacetone, iron (III) hexafluoroacetylacetone, iron (II) benzoylacetone, iron (III) benzoylacetone, 2,
2,6,6-tetramethyl-3,5-heptanedioneiron (II) and 2,2,6,6-tetramethyl-3,5
-Heptanedione iron (III).

Some specific examples of suitable iron alkoxides or aryl oxides include iron (II) methoxide, iron (III) methoxide, iron (II) ethoxide, iron (III) ethoxide, iron (II) isopropoxide. , Iron (III) isopropoxide, iron (II) 2-ethylhexoxide, iron (III) 2-
Ethylhexoxide, iron (II) phenoxide, iron (III) phenoxide, iron (II) nonylphenoxide, iron (III) nonylphenoxide, iron (I
I) naphthoxide and iron (III) naphthoxide.

Some examples of suitable iron halides include iron (II) fluoride, iron (III) fluoride, iron chloride (I
I), iron (III) chloride, iron (II) bromide, iron bromide (I
II) and iron (II) iodide.

Some representative examples of suitable pseudoiron halides include iron (II) cyanide, iron (II) cyanide
I), iron (II) cyanate, iron (III) cyanate, iron (II) thiocyanate, iron (III) thiocyanate, iron (II) azide, iron (III) azide and iron ferrocyanide ( III) (also called Prussian blue).

The term "organic iron compound" as used herein refers to any iron compound containing at least one covalent iron-carbon bond. Some specific examples of suitable organoiron compounds include bis (cyclopentadienyl) iron (II) (also called ferrocene), bis (pentamethylcyclopentadienyl) iron (II) (also decamethylferrocene). Bis (pentadienyl) iron (II),
Bis (2,4-dimethylpentadienyl) iron (II),
Bis (allyl) dicarbonyliron (II), (cyclopentadienyl) (pentadienyl) iron (II), tetra (1-norbornyl) iron (IV), (trimethylenemethane) tricarbonyliron (II), bis ( (Butadiene) carbonyliron (II), (butadiene) tricarbonyliron (0) and bis (cyclooctatetraene) iron (0)
Is included.

Component (b) of the catalyst composition of the present invention has the following keto-enol tautomeric structure:

[0026]

Embedded image

Wherein R ¹ and R ² may be the same or different and are a hydrocarbyl group selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl, alkaryl and allyl groups, wherein ,
The number of carbon atoms in each group is preferably 1 or the minimum number appropriate to form the group (often 3 or 6)
To 20 or less carbon atoms.] Dihydrocarbyl hydrogen phosphite. This dihydrocarbyl hydrogen phosphite exists mainly as a keto tautomer (shown on the left) and an enol tautomer (shown on the right)
Is a minor species. Either of the two tautomers or a mixture thereof is used as the component (b) of the catalyst composition of the present invention.
Can be used as The equilibrium constant for the above-described tautomeric equilibrium depends on factors such as temperature, types of R ¹ and R ² groups, type of solvent, and the like. Both tautomers can be present in dimeric, trimer or oligomeric form by bonding via hydrogen bonds.

Some representative examples of suitable dihydrocarbyl hydrogen phosphites are dimethyl hydrogen phosphite, diethyl hydrogen phosphite, dibutyl hydrogen phosphite, dihexyl hydrogen phosphite, dioctyl hydrogen phosphite, didecyl hydrogen phosphite, didodecyl hydrogen phosphite. Phyte, dioctadecyl hydrogen phosphite, bis (2,
2,2-trifluoroethyl) hydrogen phosphite, diisopropyl hydrogen phosphite, bis (3,3-dimethyl-2-butyl) hydrogen phosphite, bis (2,4-dimethyl-3-pentyl) hydrogen phosphite, di -T-butyl hydrogen phosphite, bis (2-ethylhexyl) hydrogen phosphite, dineopentyl hydrogen phosphite, bis (cyclopropylmethyl) hydrogen phosphite, bis (cyclobutylmethyl) hydrogen phosphite, bis (cyclopentylmethyl) hydrogen phosphite Phyto, bis (cyclohexylmethyl) hydrogen phosphite, dicyclobutyl hydrogen phosphite, dicyclopentyl hydrogen phosphite, dicyclohexyl hydrogen phosphite, dimethyl hydrogen phosphite, diphenyl hydrogen phosphite, dinaphthyl hydrogen phosphite, diben Hydrogen phosphite, bis (1-naphthylmethyl) hydrogen phosphite, diallyl hydrogen phosphite, dimethallyl hydrogen phosphite, dicrotyl hydrogen phosphite, ethyl butyl hydrogen phosphite, methylhexyl hydrogen phosphite, methyl neopentyl hydrogen phosphite, methyl Phenyl hydrogen phosphite, methylcyclohexyl hydrogen phosphite, methylbenzyl hydrogen phosphite and the like. Also, mixtures of the above dihydrocarbyl hydrogen phosphites can be used.

The catalyst composition of the present invention further comprises an organoaluminum compound as component (c). The term "organoaluminum compound" as used herein refers to any aluminum compound containing at least one covalent aluminum-carbon bond. In general, the use of organoaluminum compounds which are soluble in the hydrocarbon medium for the polymerization is advantageous. A preferred type of organoaluminum compound that can be used in the catalyst composition of the present invention is a compound of the general formula AlR _n X _3-n (n = 1,
2 or 3) wherein each R is the same or different and is a hydrocarbyl group selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl, alkaryl and allyl groups, wherein each The number of carbon atoms in the R group is preferably from 1 or the minimum number (often 3 or 6) suitable for forming said group.
And each X is the same or different and is hydrogen, halogen, preferably chlorine or bromine, or an alkoxide or aryloxide group having 1 or 6 to 20 carbon atoms. ]. Thus, suitable types of organoaluminum compounds that can be used in the catalyst composition of the present invention include:
Although not limited to these, trihydrocarbyl aluminum, dihydrocarbyl aluminum hydride, hydrocarbyl aluminum dihydride, dihydrocarbyl aluminum halide, hydrocarbyl aluminum dihalide, dihydrocarbyl aluminum alkoxide, hydrocarbyl aluminum dialkoxide, dihydrocarbyl aluminum aryl oxide , Hydrocarbyl aluminum diaryl oxides, and the like, and mixtures thereof. Generally, trihydrocarbyl aluminum compounds are preferred.

Some specific examples of suitable organoaluminum compounds that can be used in the catalyst composition of the present invention include trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-propylaluminum, triisopropylaluminum, triisopropylaluminum, n
-Hexyl aluminum, tri-n-octyl aluminum, tricyclohexyl aluminum, triphenyl aluminum, tri-p-tolyl aluminum, tribenzyl aluminum, diethyl phenyl aluminum,
Diethyl-p-tolyl aluminum, diethyl benzyl aluminum, ethyl diphenyl aluminum, ethyl-di-p-tolyl aluminum, ethyl dibenzyl aluminum, diethyl aluminum hydride, di-n
-Propyl aluminum hydride, diisopropyl aluminum hydride, di-n-butyl aluminum hydride, diisobutyl aluminum hydride, di-n-octyl aluminum hydride, diphenyl aluminum hydride, di-p-tolyl aluminum hydride, dibenzyl aluminum hydride, phenylethyl aluminum hydride Phenyl n-propyl aluminum hydride, phenyl isopropyl aluminum hydride, phenyl n
-Butyl aluminum hydride, phenyl isobutyl aluminum hydride, phenyl n-octyl aluminum hydride, p-tolyl ethyl aluminum hydride, p-tolyl n-propyl aluminum hydride, p-tolyl isopropyl aluminum hydride, p-tolyl n-butyl aluminum hydride, p -Tolyl isobutyl aluminum hydride, p-tolyl n-octyl aluminum hydride, benzyl ethyl aluminum hydride, benzyl n-propyl aluminum hydride, benzyl isopropyl aluminum hydride, benzyl n-butyl aluminum hydride, benzyl isobutyl aluminum hydride, benzyl n-octyl aluminum hydride Ethylaluminum dihydride, n- propyl aluminum dihydride, isopropyl aluminum dihydride, n- butylaluminum dihydride, isobutylaluminum dihydride, n- octyl aluminum dihydride,
Dimethylaluminum chloride, diethylaluminum chloride, dimethylaluminum bromide, diethylaluminum bromide, dimethylaluminum fluoride, diethylaluminum fluoride, methylaluminum dichloride, ethylaluminum dichloride, methylaluminum dibromide, ethylaluminum dibromide, methylaluminum difluoride, Ethyl aluminum difluoride, methyl aluminum sesquichloride, ethyl aluminum sesquichloride, isobutyl aluminum sesquichloride, dimethyl aluminum methoxide, diethyl aluminum methoxide, diisobutyl aluminum methoxide, dimethyl aluminum ethoxide, diethyl aluminum ethoxide Oxide, diisobutylaluminum ethoxide, dimethylaluminum phenoxide, diethylaluminum phenoxide, diisobutylaluminum phenoxide, methylaluminum dimethoxide, ethylaluminum dimethoxide, isobutylaluminum dimethoxide, methylaluminumdiethoxide, ethylaluminumdiethoxy Sides, isobutylaluminum diethoxide, methylaluminum diphenoxide, ethylaluminum diphenoxide, isobutylaluminum diphenoxide, and the like, and mixtures thereof.

The catalyst composition of the present invention contains the above three components (a), (b) and (c) as main components. If desired, in addition to the three catalyst components (a), (b) and (c), it is also possible to add other catalyst components, such as other organometallic compounds (known in the art). is there.

The catalyst compositions of the present invention exhibit very high catalytic activity over a wide range of overall catalyst concentrations and catalyst component ratios. The three catalyst components (a), (b) and (c) apparently interact to form an active catalyst species. Therefore,
The optimum concentration of any one catalyst component depends on the concentrations of the other two catalyst components. While polymerization occurs over a wide range of catalyst concentrations and catalyst component ratios, the range of catalyst concentrations and catalyst component ratios that results in polymers exhibiting the most desirable properties is narrower.

In the catalyst composition of the present invention, the molar ratio of dihydrocarbyl hydrogen phosphite to the iron-containing compound (P / F
e) can vary from about 0.5: 1 to about 50: 1, with about 1: 1 to about 25: 1 being a more preferred range, and about 2: 1 to about 10: 1. This is the most preferable range.
Molar ratio of organoaluminum compound to iron-containing compound (Al
/ Fe) can vary from about 1: 1 to about 100: 1. However, a more preferred range for the Al / Fe molar ratio is from about 3: 1 to about 50: 1, and the most preferred range is from about 5: 1 to about 20: 1.

The concentration of the entire catalyst in the polymerization mass depends on the purity of the above components, the desired polymerization rate and conversion,
It depends on factors such as the polymerization temperature. Therefore, it is not possible to explicitly state the specific overall catalyst concentration, other than stating that the individual catalyst components should be used in catalytically effective amounts. The amount of iron-containing compound used can generally vary from about 0.01 to about 2 mmol / 100 g of 1,3-butadiene, but a more preferred range is from about 0.02 to about 2/100 g of 1,3-butadiene. 1.0 mmol, the most preferred range being from about 0.05 to about 0.5 mmol per 100 g of 1,3-butadiene. This example, which is provided for purposes of illustrating the teachings of the present invention, illustrates certain specific overall catalyst concentrations and catalyst component ratios that result in polymers of the desired properties.

The three catalyst components of the present invention can be introduced into the polymerization apparatus in several different ways. Thus, the three catalyst components can be combined with the monomer /
The catalyst may be formed in situ by adding to the solvent mixture, and when the above components are added in a stepwise manner, the order of addition of these components is not critical, but preferably the iron-containing compound , Dihydrocarbyl hydrogen phosphite, and finally an organoaluminum compound. Alternatively, the three catalyst components may also be pre-applied to a suitable temperature outside the polymerization apparatus (e.g., from about
C), the resulting mixture can be added to a polymerization apparatus. In addition, it is also possible to pre-form the catalyst, i.e. to add a small amount of 1 to the main part of the monomer / solvent mixture to be polymerized before charging the three catalyst components. At a suitable temperature in the presence of a 1,3-butadiene monomer (e.g.
℃). The amount of 1,3-butadiene monomer used when pre-forming the catalyst may range from about 1 to about 500 moles per mole of iron-containing compound, preferably 1 mole of iron-containing compound. It should be from about 4 to about 50 moles per. In addition, it is also possible to introduce the three catalyst components into the polymerization apparatus in a two-stage process.
Such a procedure involves first iron-containing compounds and organoaluminum compounds in the presence of small amounts of the 1,3-butadiene monomer as specified above at a suitable temperature (e.g., about -20.
(About 80 ° C. to about 80 ° C.). Next, the resulting reaction mixture and dihydrocarbyl hydrogen phosphite are added to the main portion of the monomer / solvent mixture in either a stepwise or simultaneous manner. It is also possible to use an alternative two-stage method. This is because the iron-containing compound and the dihydrocarbyl hydrogen phosphite are first reacted at an appropriate temperature (for example, about -20 ° C to about 80 ° C) to form an iron complex, and then the obtained iron complex and the organoaluminum compound To the monomer / solvent mixture in either a stepwise or simultaneous manner.

When the solution containing the catalyst component is formed outside the polymerization apparatus, the organic solvents usable in the solution of the catalyst component include aromatic hydrocarbons, aliphatic hydrocarbons and cycloaliphatic hydrocarbons, and It can be selected from a mixture of two or more of the hydrocarbons mentioned above. Preferably, the organic solvent comprises at least one selected from benzene, toluene, xylene, hexane, heptane and cyclohexane.

As described hereinabove, the iron-based catalyst composition of the present invention containing the three catalyst components (a), (b) and (c) is syndiotactic 1,2- Very high catalytic activity in the production of polybutadiene. Accordingly, the present invention further provides a method for producing syndiotactic 1,2-polybutadiene using the above-described iron-based catalyst composition.

The above three catalyst components (a) based on iron,
Polymerizing the 1,3-butadiene monomer in the presence of a catalyst composition comprising (b) and (c),
The syndiotactic 1,2-polybutadiene production according to the method of the invention is put to practical use. As described above, there are various methods available for contacting the three components of the catalyst composition of the present invention with the 1,3-butadiene monomer.

According to the method of the present invention, the polymerization of the 1,3-butadiene monomer can be carried out by bulk polymerization (in the bulk polymerization, no solvent is used). Such bulk polymerization can be carried out either in the condensed liquid phase or in the gas phase.

Alternatively, the 1,3- according to the method of the present invention
The polymerization of butadiene is more typically performed using an organic solvent as a diluent. In this case, the 1,3 to be polymerized
A solution polymerization system can be used when both the butadiene monomer and the resulting polymer can be dissolved in the polymerization medium. Alternatively, a suspension polymerization system can be used by selecting a solvent in which the resulting polymer is insoluble. In both cases, a certain amount of the organic solvent is usually added to the polymerization apparatus in addition to the organic solvent contained in the solution of the catalyst component. The additional organic solvent may be the same as the organic solvent contained in the solution of the catalyst component, or may be different. Generally, it is desirable to select an organic solvent that is inert with respect to the present catalyst composition used in the polymerization catalyst. Suitable types of organic solvents that can be used as diluents include, but are not limited to, aliphatic hydrocarbons,
Cycloaliphatic and aromatic hydrocarbons are included.
Some representative examples of suitable aliphatic solvents include n-pentane, n-hexane, n-heptane, n-octane, n-octane.
Nonane, n-decane, isopentane, isohexanes,
Isoheptanes, isooctanes, 2,2-dimethylbutane, petroleum ether, kerosene, mineral spirits and the like are included. Some representative examples of suitable cycloaliphatic solvents include cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, and the like. Some representative examples of suitable aromatic solvents include benzene, toluene, xylenes, ethylbenzene, diethylbenzene,
Mesitylene and the like. Commercial mixtures of the above hydrocarbons can also be used. For environmental reasons, aliphatic and cycloaliphatic solvents are very suitable.

The range of the concentration of the 1,3-butadiene monomer to be polymerized is not particularly limited. However, in general, the 1,3 present in the polymerization medium at the start of the polymerization
The concentration of butadiene monomer is preferably in the range from about 3% to about 80% by weight, more preferably about 5% by weight
To about 50% by weight, with the most preferred range being from about 10% to about 30% by weight.

In carrying out the polymerization of 1,3-butadiene according to the process of the present invention, the resulting syndiotactic 1,1
For controlling the molecular weight of 2-polybutadiene, it is also possible to use a molecular weight regulator. As a result, the range of polymerization systems can range from very high molecular weight polymers to low molecular weight polymers, syndiotactic 1,2-.
It is also possible to extend the manner available in the production of polybutadiene. Suitable types of molecular weight regulators that can be used include, but are not limited to, accumulation (a
cucmulated) diolefins such as allene and 1,2-butadiene; non-conjugated diolefins such as 1,6-octadiene, 5-methyl-1,4.
-Hexadiene, 1,5-cyclooctadiene, 3,7
-Dimethyl-1,6-octadiene, 1,4-cyclohexadiene, 4-vinylcyclohexene, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,6-heptadiene, 1,2-divinyl Cyclohexane, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-vinyl-2-norbornene, dicyclopentadiene, 1,2,4-trivinylcyclohexane and the like; acetylenes such as acetylene, methylacetylene and Vinyl acetylene and the like; and mixtures thereof. The amount of such molecular weight modifier used (expressed in parts per hundred parts by weight (phm) of the 1,3-butadiene monomer used in the polymerization (phm)) ranges from about 0.01 to about 10 phm, preferably about 0.02 phm.
To about 2 phm, most preferably from about 0.05 to about 1 phm. In addition, by conducting the polymerization of the 1,3-butadiene monomer in the presence of hydrogen,
It is also possible to effectively control the molecular weight of the resulting syndiotactic 1,2-polybutadiene product.
In this case, it is appropriately selected so that the partial pressure of hydrogen is in the range of about 0.01 to about 50 atmospheres.

According to the process of the present invention, the polymerization of 1,3-butadiene can be carried out in a batch process, a semi-continuous process, or a continuous process. In any case, the polymerization is carried out under anaerobic conditions with an inert protective gas, such as nitrogen, argon or helium, with moderate to vigorous stirring. The polymerization temperature used in the practice of the present invention is low, for example,-
From temperatures of 10 ° C. or less to high temperatures, for example
It can vary widely over temperatures of ° C or higher, with a preferred temperature range of about 20 ° C to about 90 ° C. The heat of polymerization can be removed using external cooling, using cooling by evaporating the 1,3-butadiene monomer or solvent, or using a combination of the two methods. The polymerization pressure used in the practice of the present invention can also vary widely, with a preferred pressure range from about 1 atmosphere to about 10 atmospheres.

When the polymerization reaction of the present invention reaches a desired conversion, the polymerization reaction can be stopped by adding a known polymerization terminator to the polymerization apparatus to deactivate the catalyst system. Conventional solvent removal and drying steps as known and typically used by those skilled in the art of producing conjugated diene polymers can be performed. The terminating agent used to deactivate the catalyst system is typically a protic compound,
This includes, but is not limited to, alcohols, carboxylic acids, inorganic acids and water, or combinations thereof. An antioxidant such as 2,6-di-tert-butyl-4-methylphenol can be added before or after the addition of such a terminator.
The amount of such antioxidants typically ranges from 0.2% to 1% by weight of the polymer product. At the time when the polymerization reaction is stopped, the polymer is precipitated by using an alcohol such as methanol, ethanol or isopropanol, or the solvent and the unreacted 1,3-butadiene monomer are distilled off with steam, followed by filtration, thereby obtaining a syndite. The tactic 1,2-polybutadiene product can be isolated from the polymerization mixture. The drying of the product is then carried out at a temperature in the range of about 25 ° C to about 100 ° C (preferably about 6 ° C).
(0 ° C.) under constant vacuum.

The syndiotactic 1,2-polybutadiene produced using the catalyst composition of the present invention has various melting temperatures depending on the components and component ratio of the catalyst. This melting temperature desirably ranges from about 90 ° C to about 2 ° C.
It may vary up to 15 ° C, more preferably from about 100 to about 200 ° C, preferably from about 110 to about 190 ° C. The content of 1,2-bonds is desirably from about 50 to about 9
9%, more preferably about 60 to about 98%, preferably about 70 to about 98%. Syndiotacticity is
Preferably from about 50 to about 99%, more preferably from about 6
0 or 70 to about 98%.

The syndiotactic 1,2-polybutadiene produced using the catalyst composition of the present invention has many uses. It can be blended with various rubbers to improve its properties. For example, it can be added to an elastic polymer to improve the green strength of the elastic polymer (especially in tires). The tire supporting carcass (reinforcing carcass) tends to deform, especially during the tire building and curing procedure. For this reason, the addition of syndiotactic 1,2-polybutadiene to the rubber composition used in the tire supporting carcass is particularly useful to prevent or minimize such deformation. . In addition, the addition of syndiotactic 1,2-polybutadiene to the tire tread composition may reduce the extent to which heat builds up in the tire and improve its wear characteristics. Syndiotactic 1,2-polybutadiene products are also useful in the production of food grade films and in numerous molding applications.

The practice of the present invention will be further described by reference to the following examples, which should not be construed, however, as limiting the scope of the invention. Parts and percentages shown in the examples are by weight unless otherwise specified.

[0048]

EXAMPLE 1 A one-liter oven-dried glass bottle was capped with a self-sealing rubber liner and a perforated metal cap and purged with a stream of dry nitrogen. ). 6 bottles of hexane in this bottle
4 g and a 1,3-butadiene content of 26.9% by weight
186 g of 1,3-butadiene / hexane blend
I charged. The following catalyst components were added to the bottle in the following order: (1) Iron (II) 2-ethylhexanoate was added at 0.0
50 mmol, (2) bis (2-ethylhexyl) hydrogen phosphite 0.20 mmol, and (3) triisobutylaluminum 0.75 mmol. The bottle was shaken for 4 hours in a water bath maintained at 50 ° C.
2,6-di-t-butyl-4-methylphenol is 0.1%.
The polymerization was stopped by adding 10 ml of 5 g of isopropanol. This polymerization mixture was added to 3 liters of isopropanol. The polymer was isolated by filtration and then dried under vacuum at 60 ° C. to constant weight. The polymer yield was 47.5 g (95%). The melting temperature of this polymer measured by differential scanning calorimetry (DSC) was 187 ° C. The polymer is ¹ H and
As a result of analysis by ¹³ C nuclear magnetic resonance (NMR), the 1,2-bond content was 90.9% and the syndiotacticity was 9%.
It was found to be 3.7%. The polymer had a weight average molecular weight (M _w ) of 1,288,000, a number average molecular weight (M _n ) of 650,000, and a polydispersity index (M _w / M) as measured by gel permeation chromatography (GPC). _n )
Was 1.9. Table I summarizes the monomer charge, the amount of catalyst component and the properties of the resulting syndiotactic 1,2-polybutadiene.

Example 2-6 In Example 2-6, the procedure of Example 1 was repeated, except that the catalyst ratio was changed as shown in Table I. Table I summarizes the monomer charge, the amount of catalyst component and the properties of the syndiotactic 1,2-polybutadiene obtained in each example.

[0050]

[Table 1]

Example 7-13 In Example 7-13, iron (II) 2-ethylhexanoate was used.
The procedure of Example 1 was repeated except that the catalyst ratio was changed as shown in Table II using iron (III) 2-ethylhexanoate instead of Table II summarizes the monomer charge, the amount of catalyst component and the properties of the syndiotactic 1,2-polybutadiene obtained in each example.

[0052]

[Table 2]

Example 14-20 In Example 14-20, iron 2-ethylhexanoate (I
Example 1 with the exception that the catalyst ratio was changed as shown in Table III, using iron (III) 2-ethylhexanoate instead of I) and using dineopentyl hydrogen phosphite instead of bis (2-ethylhexyl) hydrogen phosphite. Procedure was repeated. Table III summarizes the monomer charge, the amount of catalyst component and the properties of the syndiotactic 1,2-polybutadiene obtained in each example.

[0054]

[Table 3]

Examples 21-26 In Examples 21-26, iron 2-ethylhexanoate (I
Example 1 except that the catalyst ratio was changed as shown in Table IV using iron (III) 2-ethylhexanoate instead of I) and dibutyl hydrogen phosphite instead of bis (2-ethylhexyl) hydrogen phosphite. Procedure was repeated. Table IV summarizes the monomer charge, the amount of catalyst components and the properties of the syndiotactic 1,2-polybutadiene obtained in each example.

[0056]

[Table 4]

Example 27-31 In Example 27-31, iron 2-ethylhexanoate (I
Example 1 with the exception that iron (III) 2-ethylhexanoate was used instead of I) and dimethyl hydrogen phosphite was used instead of bis (2-ethylhexyl) hydrogen phosphite and the catalyst ratio was changed as shown in Table V Procedure was repeated. Table V summarizes the monomer charge, the amount of catalyst component and the properties of the syndiotactic 1,2-polybutadiene obtained in each example.

[0058]

[Table 5]

Examples 32-38 In Examples 32-38, iron 2-ethylhexanoate (I
The procedure of Example 1 was repeated except that iron (III) acetylacetone was used instead of I) and the catalyst ratio was changed as shown in Table VI. Table VI summarizes the monomer charge, the amount of catalyst component and the properties of the syndiotactic 1,2-polybutadiene obtained in each example.

[0060]

[Table 6]

Examples 39-45 In Examples 39-45, iron 2-ethylhexanoate (I
The procedure of Example 1 is repeated except that the catalyst ratio is changed as shown in Table VII using iron (III) acetylacetone instead of I) and using dineopentyl hydrogen phosphite instead of bis (2-ethylhexyl) hydrogen phosphite. Was. Table VII summarizes the monomer charge, the amount of catalyst components and the properties of the syndiotactic 1,2-polybutadiene obtained in each example.

[0062]

[Table 7]

Examples 46-52 In Examples 46-52, iron 2-ethylhexanoate (I
The procedure of Example 1 was repeated except that the catalyst ratio was changed as shown in Table VIII using iron (III) acetylacetone instead of I) and triethylaluminum instead of triisobutylaluminum. Table VII shows the charged monomer, the amount of the catalyst component, and the characteristics of the syndiotactic 1,2-polybutadiene obtained in each Example.
Summarized in I. Analysis of the polymer produced in Example 48 by ¹ H and ¹³ C NMR showed that the 1,2-bond content was 84.6% and the syndiotacticity was 74.5%.

[0064]

[Table 8]

Examples 53-58 In Examples 53-58, iron 2-ethylhexanoate (I
Using iron (III) acetylacetone instead of I),
The procedure of Example 1 was repeated except that the catalyst ratio was changed as shown in Table IX using dineopentyl hydrogen phosphite instead of bis (2-ethylhexyl) hydrogen phosphite and using triethyl aluminum instead of triisobutyl aluminum. Table IX summarizes the monomer charge, the amount of catalyst component and the properties of the syndiotactic 1,2-polybutadiene obtained in each example.

[0066]

[Table 9]

Example 59 A glove box was operated under a nitrogen atmosphere in which 32.4 mg (0.20 mg) of anhydrous iron (III) powder was placed in an oven-dried 1 liter glass bottle.
Mmol). The bottle was capped with a self-sealing rubber liner and a perforated metal cap, and then removed from the glove box. Add 1 hexane to this bottle
368 of a 1,3-butadiene / hexane blend having a content of 32 g and a 2,3-butadiene content of 27.2% by weight.
After charging, 0.80 mmol of bis (2-ethylhexyl) hydrogen phosphite and 2.80 mmol of triisobutylaluminum were charged. 50 bottles of this
Shake for 4 hours in a water bath maintained at ° C. The treatment of the polymerization mixture was carried out in a manner similar to that described in Example 1 to give 37.2 g (37% yield) of polymer. The melting temperature of this polymer measured by DSC was 168 ° C. The weight average molecular weight ( _Mw ) of this polymer measured by GPC was 871,000, the number average molecular weight ( _Mn ) was 329,000, and the polydispersity index ( _Mw / _Mn ) was 2.6. Was.

Although the present invention has been described by reference to particular means, materials and embodiments in the examples given above,
It will be apparent to those skilled in the art that various modifications and variations can be made that fall within the scope of the invention as set forth in the appended claims. Accordingly, the invention is not limited to the details disclosed, but extends to all equivalents falling within the scope of the claims.

Claims (2)

[Claims] 1. A catalyst composition comprising: a) an iron-containing compound; b) dihydrocarbyl hydrogen phosphite; and c) an organoaluminum compound. 2. A process for the preparation of syndiotactic 1,2-polybutadiene, comprising: a) a catalyst composition comprising: a) an iron-containing compound, b) dihydrocarbyl hydrogen phosphite, and c) an organoaluminum compound. A method comprising polymerizing 1,3-butadiene in the presence of an effective amount.